.\" Copyright (c) 2011 Kai Wang
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.\" $Id: dwarf_add_AT_location_expr.3 3640 2018-10-14 14:09:13Z jkoshy $
.\"
.Dd September 5, 2011
.Dt DWARF_ADD_AT_LOCATION_EXPR 3
.Os
.Sh NAME
.Nm dwarf_add_AT_location_expr
.Nd create an attribute descriptor for a location expression
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft "Dwarf_P_Attribute"
.Fo dwarf_add_AT_location_expr
.Fa "Dwarf_P_Debug dbg"
.Fa "Dwarf_P_Die die"
.Fa "Dwarf_Half attr"
.Fa "Dwarf_P_Expr loc_expr"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
Function
.Fn dwarf_add_AT_location_expr
creates an attribute descriptor for a location expression and attaches
it to the debugging information entry referenced by argument
.Ar die .
.Pp
Argument
.Ar dbg
should reference a DWARF producer instance allocated using
.Xr dwarf_producer_init 3
or
.Xr dwarf_producer_init_b 3 .
.Pp
Argument
.Ar die
should reference a debugging information entry allocated using
.Xr dwarf_new_die 3 .
.Pp
Argument
.Ar attr
specifies the attribute code of the created attribute descriptor.
.Pp
Argument
.Ar loc_expr
should reference a location expression descriptor allocated using
.Xr dwarf_new_expr 3 .
.Pp
The attribute created by function
.Fn dwarf_add_AT_location_expr
will have one of the DWARF forms
.Dv DW_FORM_block ,
.Dv DW_FORM_block1 ,
.Dv DW_FORM_block2
or
.Dv DW_FORM_block4 ,
depending on the size of the byte stream generated by the location
expression descriptor referenced by argument
.Ar loc_expr .
.Pp
If argument
.Ar err
is not NULL, it will be used by to store error information in case of
an error.
.Sh RETURN VALUES
On success, function
.Fn dwarf_add_AT_location_expr
returns the created attribute descriptor.
In case of an error, function
.Fn dwarf_add_AT_location_expr
returns
.Dv DW_DLV_BADADDR
and sets the argument
.Ar err .
.Sh ERRORS
Function
.Fn dwarf_add_AT_location_expr
can fail with:
.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
.It Bq Er DW_DLE_ARGUMENT
One of the arguments
.Ar dbg ,
.Ar die
or
.Ar loc_expr
was NULL.
.It Bq Er DW_DLE_MEMORY
An out of memory condition was encountered during the execution of the
function.
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_new_die 3 ,
.Xr dwarf_new_expr 3 ,
.Xr dwarf_producer_init 3 ,
.Xr dwarf_producer_init_b 3
